A 10-inch steel plate at 170 yards is about 5.8 MoA. As you can see in the video, the Burris XTR II reticle used has an interior dimension of 1.75 mils (about 6 MoA) which appears just slightly larger than the target.

For reference, basic Army and Marine rifle grouping standard is a 6 MoA group (4cm at 25 yards) fired prone supported. Mr. Kelley is performing this demo offhand unsupported. That’s the skill difference between military-trained personnel and a good competition shooter.